For many years, research in cognitive and social psychology has emphasized the importance of the subject's awareness of his-own mental entities (measured by introspection) for the explanation of human behavior. Recently, Nisbett and Wilson (1977b) have come to a provocative antiintrospectivist conclusion (AIC). Based on a review of experimental evidence, they suggest that (a) people have little or no access to their own mental processes, and (b) when people do try to explain their own behavior, they base their explanations on existing available theories instead of their introspections. Here is a summary of their major points: "Evidence is reviewed which suggests that there may be a little or no direct introspective access to higher order cognitive processes. Subjects are sometimes (a) unaware of th-e existence of a stimulus that importantly influenced a response, (b) unaware of the existence of the response, and (c) unaware that the stimulus has affected the response. It is proposed here that when people attempt to report on their cognitive processes, that is, on the processes mediating the effects of a stimulus on a response, they do not do soon the basis of any true introspection. Instead their reports are based on a priori, implicit causal theories, or judgement, about the extent to which a particular stimulus is a plausible cause of a given response."(P. 231)The purpose of this paper is (a) to isolate the flaws in the way Nisbett and Wilson reached the AIC and the "available theory" thesis, and (b) to develop an alternative model-the "hypothesizing from introspections" (HI) model-which emphasizes the possibility of a person's access to his mental entities. The article emphasizes the following points: First, a brief clarification of Nisbett and Wilson's differentiation between mental processes and mental contents will be given (for the sake of clarity I will use the term mental entities as a general category for what people can become aware 09.Second, the way in which Nisbett and Wilson reached the AIC and the logical structure of their arguments will be described. Third, based on Nisbett and Wilson's differentiations between the subject's awareness of the 2 12 Sam S. Rakover stimulus, the response, and the processes by which one leads to the other, a model is developed according to which the subject is conceived of as a scientist who plans his internal observations and who hypothesizes from his mental entities. Fourth, some of Nisbett and Wilson's experiments will be reanalyzed from the point of view of the proposed model. Finally in the light of the HI model, Nisbett and Wilson's non-self report criterion for determining the subject awareness will be discussed.Nisbett and Wilson's paper has generated many criticisms, most of them are methodological (e.g., Smith and Miller, 1978;White, 1980;Adair and Spinner, 1981). In comparison, the present paper presents on the one hand a philosophical critique, and on the other an alternative model-the HI model-which accounts for Nisbett and Wilson's empirical results.